A) Field of the Invention
This invention relates to a coil element for a data carrier with an integrated circuit and noncontacting coupling, in particular an IC card, and a method for producing such a coil element.
B) Related Technology
IC cards are used in different areas of application, for example as telephone cards, credit cards, check cards, identity cards, etc.
An IC card generally has a contact array or bank for coupling an IC embedded in the card with an external data processing apparatus. For this purpose the data processing apparatus has a counterpart to the IC card contact array which can be electrically connected with the contact array when required.
IC cards are also known which have a coil instead of the contact array or in addition to the contact array. This coil permits contactless data and energy transfer between the IC card and the data processing apparatus by means of electromagnetic radiation. The coil is embedded in the card body during production of the IC card. Various methods are known for equipping an IC card with a coil.
It is known from U.S. 4,999,742 to bond a wound wire coil onto a substrate and then cover it with a cover film or layer. Since the wire coils generally consist of very thin wire and only few turns, these wire coils are very difficult to handle and to place exactly on the substrate. The wire coils readily bend or deform during transport from the coil manufacturer to the card manufacturer and must therefore be elaborately packaged. Furthermore it is very difficult to position and bond the sensitive wire coils on the substrate by machine. Manual positioning and bonding is possible, but relatively expensive.
It is furthermore known from DE 44 16 697 to produce a coil in the form of a very thin metal layer on a substrate. This substrate can be integrated in a card body to produce a contactless IC card. However the production of such metal layer coils is relatively expensive and there is the danger of the metal layer being interrupted by breaking upon application of mechanical stress on the card.
The invention has an objective permitting cost-effective and largely automated production of data carriers with integrated circuits and noncontacting coupling which meet high quality requirements.